Rod-coil block polyimide copolymers

ABSTRACT

This invention is a series of rod-coil block polyimide copolymers that are easy to fabricate into mechanically resilient films with acceptable ionic or protonic conductivity at a variety of temperatures. The copolymers consist of short-rigid polyimide rod segments alternating with polyether coil segments. The rods and coil segments can be linear, branched or mixtures of linear and branched segments. The highly incompatible rods and coil segments phase separate, providing nanoscale channels for ion conduction. The polyimide segments provide dimensional and mechanical stability and can be functionalized in a number of ways to provide specialized functions for a given application. These rod-coil black polyimide copolymers are particularly useful in the preparation of ion conductive membranes for use in the manufacture of fuel cells and lithium based polymer batteries.

ORIGIN OF THE INVENTION

The invention described herein was made by an employee of the UnitedStates Government and may be manufactured and used by or for theGovernment for governmental purposes without the payment of anyroyalties thereon or therefor.

BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to rod-coil block polyimide copolymers and morespecifically to a series of rod-coil block co-polymers that are easy tofabricate, form dimensionally stable films with good ion conductivity ata wide range of temperatures for use as separator materials for avariety of applications. The polymers consist of short rigid rodsegments alternating with flexible ether coil segments. A unique featureof these polymers is that the highly incompatible rods and coils phaseseparate giving nanoscale channels for ion conduction. The conduction ofions may be in the coil phase or rod phase or both. The rod phase alsoprovides dimensional and mechanical stability to the polymer system.More specifically, suitable functionality can be introduced into therods or coil segments to produce or enhance the transport of lithiumions for lithium polymer battery applications or transport of protonsfor fuel cell applications. Other uses for these rod-coil polyimidepolymers include, but are not limited to ion sensors, chemical sensors,water purification, optical wave guides and the like.

Although the prior art fails to disclose block copolymers comprisingshort rigid polyimide rod segments alternating with polyether coilsegments as taught by this invention, the Aso et al publicationdiscloses polyimides containing ether linkages that exhibit excellentthermal and thermo-oxidative stability. These polyimides are stated tobe useful as films, composites, membranes, and adhesives; see Aso andMononori, Polyimides containing ether linkages in Concise PolymericMaterials Encyclopedia, 1202 J. C. Salamone, CRE Press, 1999.

Additional prior art includes U.S. Pat. No. 5,468,571 which discloses abattery with a negative electrode comprising carbon powder consolidatedwith a polyimide binder. The polyimide may be either a thermosettingpolyimide or a thermoplastic polyimide. A representative example ofpolyimide resins is obtained by heat curing a solution of a polyamideacid (a polyimide intermediate) in N-methyl-2-pyrrolidone. The polyamideacid is obtained by reacting an aromatic diamine with an aromatictetracarboxylic acid anhydride. U.S. Pat. No. 6,001,507 also discloses anon-aqueous electrolyte battery using a binder comprising a polyimide.The polyimides are prepared by reacting tetracarboxylic aciddianhydrides, such as pyromellitic dianhydride (PMDA), and diamines,such as bis (4-aminophenyl) ether (ODA), in an appropriate solvent toobtain polyamic acids, after which cyclodehydrating agents dehydratesthe polymer.

SUMMARY OF THE INVENTION

This invention relates to polyimide rod-coil block copolymers and morespecifically to the use of these copolymers as membrane materials forion conduction. The polymers consist of short rigid rod segmentsalternating with flexible coil segments. The rod and coil segments canbe linear, branched or mixtures of linear and branched. The polymersprovide dimensional thermal stability and good ion conductivity. Thesepolymers can be used in preparing fuel cells, lithium polymer batteries,ion sensors and the like.

The rod-coil block polyimide copolymers of this invention arecharacterized by the general formula:

wherein R₁ is selected from the group consisting of hydrogen, alkylradicals, and alkoxy radicals, R₂ is selected from the group consistingof hydrogen, alkyl radicals, and alkoxy radicals, and X is selected fromthe group consisting of aromatic radicals, heterocyclic radicals, andaliphatic radicals, wherein x is equal to or greater than zero, y isequal to or greater than zero and n is equal to or greater than one. Thealkyl or aliphatic and alkoxy radicals are radicals having from 1 to 8carbons or higher and preferably 1 to 4 carbons. R₁ and R₂ are notlimited and may include various other known substituents.

Accordingly, it is an object of this invention to provide blockcopolymers consisting of short rigid polyimide rod segments alternatingwith flexible ether coil segments.

It is another object of this invention to provide block copolymerscontaining polyimide rod segments and polyether coil segments that areeither linear, branched or a combination thereof wherein the highlyincompatible rods and coil segments may phase separate providingnonoscale channels for ion conduction.

It is another object of this invention to provide block copolymerscontaining polyimide rod segments and polyether coil segments whereinthe incompatibility between the polyimide rod and polyether coilsegments provide good phase separation, and a high degree of order inthe system wherein lithium ions can travel leading to high-ionicconductivity in the polymer for its use in preparing lithium batteries.

It is a further object of this invention to provide block copolymerscontaining polyimide rod segments and polyether coil segments for use inthe preparation of fuel cells wherein the polyether coil segments allowsthe polymer to hold water at high temperatures in comparison to thepolyimides without the polyether coil segments.

It is a further object of this invention to provide mechanicallyresilient polymeric films having ion conductivity comprising rod-coilblock polyimide copolymers.

It is still a further object of this invention to provide blockcopolymers containing polyimide rod segments and polyether coil segmentsfor use in the preparation of fuel cells wherein the polyimide rodsegment contains suitable functional groups for proton conduction andmay provide good phase separation with the polyimide polyether coilsegments.

These and object of this invention will become more apparent from afurther and more detailed description of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

This invention relates to a series of rod-coil block polyimidecopolymers that are easy to fabricate into mechanically resilient filmswith acceptable ionic or protonic conductivity at a variety oftemperatures depending on the ultimate application. The polymers consistof short-rigid polyimide rod segments alternating with flexiblepolyether coil segments. The rods and coil segments can be linear,branched or mixtures of linear and branched. The highly incompatible rodand coil segments phase separate providing nanoscale channels for ionconduction. The polyimide segments provide dimensional and mechanicalstability. In addition, the polyimide segments can be functionalized inany number of ways to provide specialized functions for a givenapplication. For example, acid groups can be placed on the polyimide rodfor proton conduction. The polyether coils have the added advantage ofbeing able to coordinate with a wide variety of organic or inorganicadditives to enhance the desired properties of the system for aparticular application. For example, it is established that polyethersare excellent coordinating agents for lithium compounds.

The commercial potential of these copolymers is quite high. The use ofthese rod-coil copolymers could substantially decrease the operatingtemperatures of lithium polymer batteries allowing for use in aerospaceand terrestrial applications. In addition, these polymers can befunctionalized for proton conduction for use as fuel cell membranes forlow and high temperature applications. The coil segments are hydrophilicwhich allow the polymers to retain moisture at higher temperatures.Ultimately, the payoffs for developing solid polymer electrolytes thatcan operate in a wide range of temperatures are safety, convenience andcost. By eliminating the need for solvents in typical batteryapplications, flammability problems are reduced, fabrication is greatlysimplified and power would not be consumed by keeping the battery warm.Moreover, by eliminating the need for excess moisture in fuel cellmembranes, fuel cells will be able to operate at elevated temperaturesproviding greater efficiency.

A unique feature of the present invention is the use of polyimidetechnology in the production of rod coil polymers. Synthesis of thepolymers is facile and versatile. In addition, the incompatibilitybetween the polyimide rod and polyether coil segments provides goodphase separation and a high degree of order in the system. For example,in lithium polymer battery applications, this ordering creates channelsin which the lithium ions can travel freely, leading to high ionicconductivity. Suitable substitution in either the rod or coil segmentscan lead to systems with lithium ion transference numbers as high asone. In fuel cell applications, the incorporation of the polyether coilsallows the polymer to hold water at higher temperatures then thepolyimide without the coils. In addition, suitable substitution and/ordoping leads to increased properties of water retention and protonconduction at a wide range of temperatures. It is also anticipated thatthe cost of producing the rod coil polymers will be significantly lowerthan the currently used perfluorosulfonic polymers.

Presently the lithium based polymer batteries for aerospace applicationsneed the ability to operate in temperatures ranging from −70 C to +70 C.Current state of the art solid polymer electrolytes (based on amorphouspolyethylene oxide, PEO) have acceptable ionic conductivities (10-4 to10-3 S/cm) only above 60 C. PEO itself has moderate lithium ionicconductivity at room temperature (10-6 S/cm). In addition, it isdifficult to process, and except for very high molecular weights, notvery dimensionally stable. Higher conductivity can be achieved in thecurrent polymer systems by adding solvent or plasticizers to the solidpolymer to improve ion transport. However, this may compromisedimensional and thermal stability of the electrolyte, as well ascompatibility with electrode materials, Hence, there is a push todevelop new electrolytes having unique molecular architecture, and/ornovel ion transport mechanisms leading to good ionic conductivity atroom temperature and below with no solvent or plasticizers. Some ofthese new approaches include comb polymers (Eectrochimica Acta, 43,1177-1184, 1998), hyperbranched systems (Macromolecules, 29, 3831-3838,1996), highly ordered Langmuir-Blodgett films (J. Power Sources, 97-98,641-643, 2001) and polyphosphazenes (Chemistry of Materials, 13,2231-2233, 2001). While all of the aforementioned approaches give ahigher conductivity then PEO, it is not high enough for futureapplications, and all suffer from poor dimensional stability.

In addition, the block polymers of this invention can be useful in thepreparation of fuel cells. Fuel cells would operate at higher efficiencyat temperatures above 80° C. due to better kinetics of redox reactionsoccurring within the cell. Catalysts are also less susceptible tocontamination at elevated temperatures. The current state of the artmaterial for polymer electrolyte membranes (PEM) for fuel cellapplications are the perfluorosulfonic polymers. In addition to theirhigh cost, the perfluorosulfonic polymers have limited utility above 80°C. due to the loss of water in the polymer membrane. The loss of waterin the polymer has been attributed to the hydrophobic nature of thepolymer backbone. This loss of water significantly reduces protonconduction in the membrane which reduces the efficiency of the fuelcell. An additional disadvantage of the perfluorosulfonic polymers infuel cell applications is the long term stability of the membranes.

The rod-coil block polyimide copolymers of this invention arecharacterized by the general formula:

wherein “Y” is an organic radical i.e. an aromatic radical substitutedaromatic radical, heterocyclic radical or aliphatic radical, R₁ isselected from the group consisting of hydrogen, alkyl radicals andalkoxy radicals, R₂ is selected from the group consisting of hydrogen,alkyl radicals and alkoxy radicals, and X is selected from the groupconsisting of aromatic radicals, substituted aromatic radicals,heterocyclic radicals, and aliphatic radicals, wherein “x” is equal toor greater than zero, “y” is equal to or greater than zero, and “n” isequal to or greater than one.

In formula I, the preferred “Y” radicals are aromatic and include, butare not limited to, the specific following formulae: II, III, IV, V andVI.

In each of the above Formulae: I, II, III, IV, and V; R₁ and R₂ are thesame or different and are selected from the group consisting ofhydrogen, alkyl radicals, and alkoxy radicals, R₃ and R₄ are the same ordifferent and are selected from the group consisting of nil, carbonylradicals, methylene radical, hexafluoroisopropylidene radical andoxygen, and R₅, R₆, R₇, and R₈ are the same or different and areselected from the group consisting of hydrogen, fluorine (F), CF₃, alkylradicals, alkoxy radicals, sulfonate radicals and alkyl sulfonateradicals, wherein “m” is equal to or greater than one, X is an aromatic,substituted aromatic, heterocyclic, or aliphatic radical “x” is equal toor greater than zero, and “y” is equal to or greater than zero and “n”is equal to or greater than one. In these formulae, the alkyl, alkoxyradicals and alkyl sulfonate radicals are radicals of 1 to 8 carbons orhigher and preferably 1 to 4 carbons.

In formula VI, R₁ and R₂ are the same or different radicals selectedfrom the group consisting of hydrogen, alkyl radicals and alkoxyradicals, “m” is equal to or greater than one, “x” is equal to orgreater than one, “y” is equal to or greater than zero, X is selectedfrom the group consisting of aromatic radicals, substituted aromaticradicals, heterocyclic radicals and alkyl radicals, and Z is an organicradical preferably selected from the group consisting of aromatic,heterocyclic and aliphatic radicals including:

wherein the above formulae, R₃ is selected from the group consisting ofnil, carbonyl radicals, oxygen, methylene radical andhexafluoroisopropylidene, and R₉ is selected from the group consistingof nitrogen, aromatic radicals, substituted aromatic radicals,heterocyclic radicals, aliphatic radicals and hydroxy aliphatic radicalswherein the aliphatic group has from 1 to 8 carbons preferably 1-4carbons such as hydroxymethyl, hydroxyethyl, hydroxypropyl and the like.

The following specific examples illustrate the method of preparing therod-coil block polyimide copolymers of this invention.

EXAMPLE 1 Synthesis of a Linear Rod-Coil Polymer

A mixture of 3.72 g 3,3′,4,4′-benzophenonetetracarboxylic dianhydrideand 15.55 g 2000 number average molecular weight polyoxyalkylene diamine(XTJ-502, Huntsman Corp.) and 0.59 g phthalic anhydride in 30 mlanhydrous tetrahydrofuran was stirred for 24 hours at room temperatureunder inert conditions to dissolve. 4,4′-diaminobenzene (0.62 g) wasadded along with another 20 ml tetrahydrofuran and stirring wascontinued to another 3 hours. The resultant highly viscous polyamic acidsolution was cast onto a flat plate. The resultant film was dried at 30°C. for 24 hours. After drying, it was cured in a vacuum oven at 200° C.for 3 hours to give 20 g of rubbery, yellow polyimide film with aformulated molecular weight of 10000. The polyamic acid solution ismixed with LiN(CF₃SO₂)₂ salt (4.99 g) and cast onto a flat plate thencured the same way as undoped film.

EXAMPLE 2 Synthesis of a Branched Rod-Coil Polymer

A mixture of 3.32 g 3,3′, 4,4′-benzophenonetetracarboxylic dianhydrideand 15.06 g 2000 number average molecular weight polyoxyalkylene diamine(XTJ-502, Huntsman Corp.) and 0.71 g phtalic anhydride in 30 mlanhydrous tetrahydrofuran was stirred for 24 hours at room temperatureunder inert conditions to dissolve.1,3,5-(4,4′,4″-triaminophenyl)-benzene (1.37 g) was added along withanother 20 ml tetrahydrofuran and stirring was continued for another 3hours. The resultant highly viscous polyamic acid solution was cast ontoa flat plate. The resultant film was dried at 30° C. for 24 hours. Afterdrying, it was cured in a vacuum oven at 200° C. for 3 hours to give 20g of rubbery, yellow polyimide film with a formulated molecular weightof 30000. The polyamic acid solution is mixed with LiN(CF₃SO₂)₂ salt(4.83 g) and cast onto a flat plate and then cured the same way asundoped film.

EXAMPLE 3 Synthesis of a Sulfonated Rod-Coil Polymer

To stirred solution of 4.116 g of 3,3′,4,4′-benzophenonetetracarboxylicdianhydride (BTDA) in 50 ml of dry 1-methyl-2-pyrrolidinone (NMP) wasadded 2.194 g of 4,4′diamino-2,2′-biphenyldisulfonic acid and 2.22 ml oftriethylamine. The solution was stirred at 110° C. for 6 hours then4.032 g of a 600 number average molecular weight polyoxyalkylene diamine(XTJ-500, Huntsman Corp.) and 0.0986 g of phthalic anhydride was added.The solution was stirred for an additional 14 hours at 110° C. Thesolution was cooled and 50 g of acidic ion-exchange resin was added(Amberlyst 15). After filtration the solution was cast onto a stainlessplate and heated to 100° C. for 14 hours and then at 200° C. for 2 hoursunder vacuum.

EXAMPLE 4 Synthesis of a Linear Rod-Coil Polymer

A mixture of 3.72 g 3,3′,4,4′-benzophenonetetracarboxylic dianhydrideand 15.55 g of a mixture of polyoxyethylene diamine and polyoxypropylenediamine and 0.59 g phthalic anhydride in 30 ml anhydrous tetrahydrofuranwas stirred for 24 hours at room temperature under inert conditions todissolve. 4,4′-diaminobenzene (0.62 g) was added along with another 20ml tetrahydrofuran and stirring was continued for another 3 hours. Theresultant highly viscous polyamic acid solution was cast onto a flatplate. The resultant film was dried at 30° C. for 24 hours. Afterdrying, it was cured in a vacuum oven at 200° C. for 3 hours to give 20g of rubbery, polyimide film.

EXAMPLE 5 Synthesis of a Sulfonated Rod-Coil Polymer

To stirred solution of 4.116 g of 3,3′,4,4′-benzophenonetetracarboxylicdianhydride (BTDA) in 50 ml of dry 1-methyl-2-pyrrolidinone (NMP) wasadded 2.194 g of 4,4′diamino-2,2′-biphenylidisulfonic acid and 2.22 mlof triethylamine. The solution was stirred at 110° C. for 6 hours then4.032 g of a mixture of polyoxyethylene diamine and polyoxypropylenediamine and 0.0986 g of phthalic anhydride was added. The solution wasstirred for an additional 14 hours at 110° C. The solution was cooledand 50 g of acidic ion-exchanged resin was added (Amberlyst 15). Afterfiltration the solution was cast onto a stainless plate and heated to100° C. for 14 hours and then at 200° C. for 2 hours under vacuum.

EXAMPLE 6 Synthesis of a Sulfonated Rod-Coil Polymer

To stirred solution of 4.116 g of 3,3′,4,4′-benzophenonetetracarboxylicdianhydride (BTDA) in 50 ml of dry 1-methyl-2-pyrrolidinone (NMP) wasadded 2.194 g of 4,4′diamino-2,2′-biphenylidisulfonic acid and 2.22 mlof triethylamine. The solution was stirred at 110° C. for 6 hours then4.032 g of polyoxyethylene diamine and 0.0986 g of phthalic anhydridewas added. The solution was stirred for an additional 14 hours at 110°C. The solution was cooled and 50 g of acidic ion-exchanged resin wasadded (Amberlyst 15). After filtration the solution was cast onto astainless plate and heated to 100° C. for 14 hours and then at 200° C.for 2 hours under vacuum.

In preparing the rod-coil block polyimide copolymers of this invention,the following are examples of the anhydrides i.e. mono and dianhydridesreacted with stoichiometric amounts of the amines i.e. the mono andpolyamines and polyoxyalkylene diamines in the ratio of about 20 to 50parts by weight of the anhydrides to about 50 to 80 parts by weight ofthe amines i.e. the mono and polyamines and polyoxyalkyl diamine. Thedianhydrides include, for example, ethylenetetracarboxylic dianhydride,butanetetracarboxylic dianhydride, cyclopentanetetracarboxylicdianhydride, pyromellitic dianhydride,3,3′,4,4′-benzophenonetetracarboxylic dianhydride,2,2′,3,3′-benzophenonetetracarboxylic dianhydride,3,3′,4,4′-biphenyltetracarboxylic dianhydride,2,2′,3,3′-biphenyltetracarboxylic dianhydride,2,2-bis(3,4-dicarboxyphenyl)propane dianhydride,2,2-bis(2,3-dicarboxyphenyl)propane dianhydride,bis(2,3-dicarboxyphenyl)ether dianhydride, bis(3,4-dicarboxyphenyl)etherdianhydride, bis(2,3-dicarboxyphenyl)sulfone dianhydride,bis(3,4-dicarboxyphenyl)sulfone dianhydride,bis(2,3-dicarboxyphenyl)methane dianhydride,bis(3,4-dicarboxyphenyl)methane dianhydride,1,1-bis(2,3-dicarboxyphenyl)ethane dianhydride,1,1-bis(3,4-dicarboxyphenyl)ethane dianhydride,1,2-bis(2,3-dicarboxyphenyl)ethane dianhydride,1,2-bis(3,4-dicarboxyphenyl)ethane dianhydride,1,3-bis(2,3-dicarboxyphenoxy)benzene dianhydride,1,3-bis(3,4-dicarboxyphenoxy)benzene dianhydride,1,3-bis(2,3-dicarboxyphenoxy)benzene dianhydride,1,4-bis(3,4-dicarboxyphenoxy)benzene dianhydride,2,3,6,7-naphthalenetetracarboxylic dianhydride,1,4,5,8-naphthalenetetracarboxylic dianhydride,1,2,5,6-naphthalenetetracarboxylic dianhydride,1,2,3,4-benzenetetracarboxylic dianhydride,3,4,9,10-perylenetetracarboxylic dianhydride,2,3,6,7-anthracenetetracarboxylic dianhydride, and1,2,7,8-phenanthrenetetracarboxylic dianhydride. Exemplary dicarboxylicmonoanhydrides include phthalic anhydride, 2,3-benzophenonedicarboylicanhydride, 3,4-benzophenonedicarboxylic anhydride, 2,3-dicarboxyphenylphenylether anhydride, 3,4-dicarboxyphenyl phenylether anhydride,2,3-biphenyldicarboxylic anhydride, 3,4-biphenyldicarboxylic anhydride,2,3-dicarboxyphenyl phenylsulfide anhydride, 3,4-dicarboxyphenylphenylsulfide anhydride, 1,2-naphthalenedicarboxylic anhydride,2,3-naphthalenedicarboxylic anhydride, naphthalenedicarboxylicanhydride, 1,2-anthracenedicarboxylic anhydride,2,3-anthracenedicarboxylic anhydride and 1,9-anthracenedicarboxylicanhydride. The anhydrides and amines can be used singly or as a mixturein various ratios.

Some of the organic solvents used in preparing the block copolymersinclude, for example, N,N-dimethylformamide; N,N-dimethylacetamide;N,N-diethylacetamide; N,N-dimethylmethoxyacetamide;N-methyl-2-pyrrolidone; bis(2-methoxyethyl)ether; tetrahydrofuran;1,3-dioxane; pyridine; dimethyl sulfoxide; dimethyl sulfone; cresol;cresylic acid; xylenol and various mixtures thereof.

The sulfonated diamines i.e. the aromatic and aliphatic diamines usefulin preparing the rod-coil copolymers can be characterized as having thegeneral formula:

wherein the preferred aromatic radicals in the above formula arecharacterized by the aromatic radicals selected from the groupconsisting of:

The sulfonated aliphatic or alkyl diamines contain alkyl groups havingup to eight carbon atoms or higher and preferably up to four carbons.Specific examples of sulfonated aromatic diamines preferably include1,4-diaminobenzene-3-sulphonic acid;4,4′-diamino-1-1′-biphenyl-2,2′-disulphonic acid;4,4′-diamino-2,2′-biphenyldisulfonic acid and various combinationsthereof. In addition to the sulfonate group i.e. the sulfonated alkyl oraryl diamines, other strong acid groups that provide high ionicconductivity in the polymeric membranes include carboxylic acid,phosphoric acid and the like.

The amines useful in preparing the block copolymers include themonamines, triamines and diamines, e.g. aromatic diamines containing atleast one benzene ring including, for example: para-phenylenediamine,4,4′-diamino-diphenylpropane, 4,4′-diamino-diphenylmethane, diaminebenzene, 1,5-diamino-napthalene, bisaniline-p-xylidene,3,3′-diaminobenzopheneone, 4,4′-diaminobenzophenone,3,3′-diaminodiphenylether, 4,4′-diaminodiphenylmethane, 3,3′-dimethylbenzidine and various triamines such as 1,3,5-triaminobenzene,4,4′,4″-triaminotriphenylmethane, 4,4′,4″-triaminotriphenylcarbinol andtriaminophenyl benzene. The monoamines include, for example, thearomatic monoamines, aniline, o-toluidine, 2,3-xylidine, 3,4-xylidine,o-aminophenol m-aminophenol, m-phenetidine, m-aminobenzaldehyde,aminobenzaldehyde, aminobenzonitrile, aminobenzonitrile,2-aminobiphenyl, 4-aminobiphenyl, 2-aminophenyl phenyl ether,3-aminophenyl phenyl ether, 2-aminobenzophenone, 3-aminobenzophenone,3-aminophenyl phenyl sulfide, naphthylamine, amino-2-naphthol,2-amino-1-naphthol and the like.

For purposes of this invention, the preferred polyoxyalkylene diaminesare alkylene diamines wherein the alkylene group has from 2 to 8 carbonsor higher, and preferably from 2 to 4 carbons such as polyoxyethylenediamine, polyoxypropylene diamines, polyoxybutylene diamine and variousmixtures thereof.

In preparing lithium-based polymer batteries with the rod-coil polyimidecopolymer films of this invention, the lithium compounds are used as theelectrolyte generally dissolved in solvent. Although the solvents arenot limited, the following examples include the carbonates such asethylene carbonate, dimethoxyethane, butyllactone, diethylether,tetrahydrofuran, methyl-tetrahydrofuran, dioxolan, acetonitrile, and thelower alkyl carbonates such as methylcarbonate, andmethylpropylcarbonate and the like. In lithium batteries, one or morelithium compounds, preferably the salts can be used including, forexample: LiClO₄, LiBF₄, LiCl, LiSO₃CH₃, LiSO₃CF₃, LiN(SO₂CF₃₎ ₂ and LiC(SO₂CF₃)₃ and various combinations thereof.

While this invention has been described with the preferred embodiments,it will be appreciated that various modifications and variations will beapparent to one skilled in the art and that such modifications andvariations are within the scope of the appended claims.

1. Rod-coil block copolymers having polyimide rod segments alternatingwith polyether coil segments derived from the reaction of approximately20 to 50 parts by weight of a mixture comprising at least one aromaticdianhydride and at least one monoanhydride and about 50 to 80 parts byweight of a mixture of amines to obtain the block copolymers; saidmixture of amines comprising at least one polyoxyalkylene-polyamine. 2.The block copolymers of claim 1 wherein the mixture of amines comprisesat least one monoamine, at least on aromatic polyamine, and at least onepolyoxyalkylenediamine.
 3. The block copolymers of claim 1 wherein atleast one polyoxyalkylene polyamine is polyoxypropylenediamine.
 4. Theblock copolymers of claim 1 wherein at least one polyoxyalkylenepolyamine is polyoxyethylenediamine.
 5. The block copolymers of claim 1wherein at least one monoanhydride is phthalic anhydride.
 6. The blockcopolymers of claim 1 wherein at least one aromatic dianhydride is3,3′,4,4′-benzophenonetetracarboxylic dianhydride.
 7. A process ofpreparing rod-coil block copolymers having polyimide rod segmentsalternating with polyether coil segments derived from the reaction ofapproximately 20 to 50 parts by weight of a mixture comprising at leastone aromatic dianhydride and at least one monoanhydride and about 50 to80 parts by weight of a mixture of amines to obtain the blockcopolymers; said mixture of amines comprising at least onepolyoxyalkylenepolyamine.
 8. The process of claim 7 wherein at least onepolyoxyalkylene polyamine is polyoxyethylenediamine.
 9. The process ofclaim 7 wherein at least one polyoxyalkylene polyamine ispolyoxypropylenediamine.
 10. The process of claim 7 wherein at least onemonoanhydride is phthalic anhydride and at least one dianhydride is3,3′,4,4′-benzophenonetetracarboxylic dianhydride.
 11. Rod-coil blockpolyimide copolymers having polyimide rod segments alternating withpolyether coil segments having the formula:

wherein Y is an organic radical, R₁ is selected from the groupconsisting of hydrogen, alkyl radicals, and alkoxy radicals, R₂ isselected from the group consisting of hydrogen, alkyl radicals, andalkoxy radicals, X is selected from the group consisting of aromaticradicals, heterocyclic radicals and aliphatic radicals, and x is equalto or greater than zero, y is equal to or greater than zero, and n isequal to or greater than one.
 12. The block polymers of claim 11 whereinx is greater than zero.
 13. The block copolymers of claim 11 wherein yis greater than zero.
 14. The block copolymers of claim 11 wherein x isgreater than zero and y is greater than zero.
 15. The rod-coil blockcopolymers of claim 11 wherein Y has the formula:

wherein R₃ and R₄ are selected from the group consisting of nil,carbonyl radicals, oxygen, methylene radical, andhexafluoroisopropylidene radical, and R₅, R₆, R₇ and R₈ are the same ofdifferent and are selected from the group consisting of hydrogen, F,CF₃, alkyl radicals, alkoxy radicals, sulfonate radicals, and alkylsulfonate radicals and m is equal to or greater than one.
 16. Therod-coil block copolymers of claim 11 wherein Y has the formula:

wherein R₅, R₆, R₇ and R₈ are the same or different and are selectedfrom the group consisting of hydrogen, F, CF₃, alkyl radicals, alkoxyradicals, sulfonate radicals, and alkyl sulfonate radicals and m isequal to or greater than one.
 17. The rod-coil copolymers of claim 16wherein the sulfonate radicals are derived from4,4′-diamino-2,2′-biphenyldisulfonic acid.
 18. The rod-coil blockcopolymers of claim 11 wherein Y has the formula:

wherein R₅, R₆, R₇ and R₈ are the same or different and are selectedfrom the group consisting of hydrogen, F, CF₃, alkyl radicals, alkoxyradicals, sulfonate radicals, and alky sulfonate radicals an m is equalto or greater than one.
 19. The rod-coil block copolymer of claim 18wherein either R₅ or R₆ is a hydrogen atom and either R₇ or R₈ is alower alkoxy radical.
 20. The rod-coil block copolymers of claim 11wherein Y has the formula:

wherein R₅, R₆, R₇ and R₈ are the same or different and are selectedfrom the group consisting of hydrogen, F, CF₃, alkyl radicals, alkoxyradicals, sulfonate radicals, and alkyl sulfonate radicals and m isequal to or greater than one.
 21. The rod-coil block copolymers of claim20 wherein either R₅, R₆, R₇ or R₈ is a sulfonate radical derived from4,4′-diamino-2,2′-biphenyl disulfonic acid.
 22. The rod-coil blockcopolymers of claim 20 wherein either R₅, R₆, R₇ or R₈ is a CF₃ radical.23. The rod-coil block copolymers of claim 11 wherein Y has the formula:

wherein R₁ is selected from the group consisting of hydrogen, alkylradicals, and alkoxy radicals, R₂ is selected from the group consistingof hydrogen, alkyl radicals, and alkoxy radicals, X is selected from thegroup consisting of aromatic radicals, heterocyclic radicals andaliphatic radicals, and x is equal to or greater than zero, y is equalto or greater than zero, and m is equal to or greater than one, and Z isa radical selected from the group consisting of aromatic radicals,heterocyclic radicals and aliphatic radicals.
 24. The rod-coil blockcopolymer of claim 23 wherein Z is an aromatic radical and x and y aregreater than one.
 25. The rod-coil block copolymer of claim 23 wherein Zis an aliphatic radical.
 26. The rod-coil block copolymer of claim 23wherein Z is a heterocyclic radical.
 27. The rod-coil block copolymersof claim 23 wherein either R₁ or R₂ is hydrogen and X is an aromaticradical.
 28. The rod-coil block copolymers of claim 23 wherein either R₁or R₂ is an alkyl radical and X is an aromatic radical.
 29. Mechanicallyresilient polymeric films having ionic conductivity at varioustemperatures comprising rod-coil block copolymers having polyimide rodsegments alternating with polyether coil segments having the formula:

wherein Y is an organic radical, R₁ is selected from the groupconsisting of hydrogen, alkyl radicals, and alkoxy radicals, R₂ isselected from the group consisting of hydrogen, alkyl radicals, andalkoxy radicals, X is selected from the group consisting of aromaticradicals, heterocyclic radicals and aliphatic radicals, and x is equalto or greater than zero, y is equal to or greater than zero, and n isequal to or greater than one.
 30. Mechanically resilient polymeric filmshaving ionic conductivity at various temperatures comprising therod-coil block copolymers of claim 29 wherein x and y are greater thanzero and Y is an aromatic radical.